


The Pruning of a Green Branch

by Kazo



Category: Fate/stay night - All Media Types
Genre: Fights, Gen, Other, Retelling of Mythology
Language: English
Status: Completed
Published: 2021-01-11
Updated: 2021-01-11
Packaged: 2021-03-15 14:54:27
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 1
Words: 4,766
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28690500
Author URL: https://archiveofourown.org/users/Kazo/pseuds/Kazo
Summary: Cu Chulainn is no stranger to tough battles, but he never expected a small child on a beach to be one of his toughest fights, and biggest regrets.
Kudos: 5





	The Pruning of a Green Branch

_**TWACK!**_

On the beaches of Ireland, a strange event was unfolding. A young indigo haired boy watched as an older man fell to the ground, a large bump on his head. With a sigh, the boy turned to a large group of grown men, staring them all down as the cape on his back flowed on the ocean’s breeze.

“I told you, not one of you is worth fighting,” The boy pointed his green spear at them, his statement given as if he was telling them the sky was blue. “Now will you let me pass, or will you keep embarrassing yourself over something as trivial as my name?”

He watched as the group grew more uncomfortable as they looked at their wounded, and how the seven year old boy in front of them had not one wound on him. He could tell what they were thinking. _“What sort of land produced such monstrous children?”_

Honestly, he was the only one who could fight like that, but it was really funny to see grown men in fear of an imaginary army of young children, so he didn’t bother correcting them. After a moment of silence, one man dressed in royal clothes spoke up.

“Only Cu Chulainn can defeat this boy,” He turned to one of the few uninjured men. “Send for him at once!” The man he commanded nodded, leaping on a horse and riding away. The boy snorted in response to that, planting his spear on the ground and sitting down, almost as if he was pouting. With a sigh, he reached into his pocket, pulling out the golden thumb ring his mother had given him before he left, admiring its beauty and using the quiet time to reflect on his current circumstances.

Right now, he wanted nothing more than to walk away from this group of weaklings and keep looking for his dad, but they had indirectly challenged him to defeat this ‘Cu Chulainn’, which his geas counted, much to his chagrin. 

He didn’t even know why he had these damn geasa in the first place. Well, he knew why, his father told his mother to put them on him when he was born… but _why_ did he? To make things worse, they weren’t something simple like ‘Don’t eat dogs’ or ‘Never refuse hospitality’, instead being three very strict ones.

‘To not answer his name when asked.’

‘To not change course.’

‘To not back down from a fight.’

Still, because of how strict they were, they were giving him a lot of power for following them, power that he needed for his journey to find his dad. There was just one tiny snag in this whole journey... he didn’t know what his dad looked like. Hell, he didn’t even know the man’s name. 

In his early years, when he asked his mom, she would never give him an answer, instead forcing him to train harder. Then when he went to his aunt for training, she also wouldn’t tell him. She only told him her greatest student would have the answer he sought.

It was like his whole family liked making his life harder, as he couldn’t pry out any more information than that, not even who this student was! So his current plan was to beat up everyone he could until he met someone who could stand up to him. That had to be Scathach’s greatest student, right?

After about an hour of nothing but the ocean waves filling the air was broken by the sound of a horse neighing, the group turning to see a blue haired man in a blue jumpsuit riding up to them. The group quietly moved to make room for the horse, the majestic animal stopping in front of the small child.

“So, is this the brat giving you all so much trouble?” The man that must have been Cu Chulainn asked, amusement laced in his voice.

“So what if I am?” the boy shot back, standing up and dusting the sand off his pants as he looked over the man. Despite the rudeness, the man just laughed. 

“You got spirit, kid,” The man complimented before shifting to a more serious tone. “Look, this has gone a little too far for just a name, hasn’t it? Just tell us your name. If you don’t, well… I don’t wanna hurt someone as young as you, but I will fight, and I _will_ win,”

“It’s not like I want to deal with all this, but I have a geas that prevents me from telling my name,” the boy retorted. “And yeah, I agree you getting humiliated just for my name is going too far, but your king’s the one that dragged it out. How about you don’t challenge me and we can move on? Because if you challenge me, then _you’re_ the one that won’t be winning,” The man sighed, shaking his head as he took in this info.

“A geas, huh? Why would you put such a stupid geas on yourself?” The man muttered, causing the boy to sputter in anger.

“Hey, shut up! My mom put it on me! She said it’d help me become a great enough warrior to stand beside my dad, the strongest warrior in all of Ireland!” The boy shouted, his hand reaching down to a sling on his side. The man only chuckled at the boy’s outrage.

“Sorry, sorry, I didn’t mean to insult your family,” The older man said with a gentle look as he watched the boy’s hand. “Well, I get your situation now. It’s a shame, but beating you is a royal order and all, so there ain’t nothing I can do about that,” The older man raised his hand, causing the boy to grab his sling, but the young kid hesitated as he watched the older man begin to draw in the air.

The boy could see that the man was drawing runes in the air, which wasn’t the biggest deal. Runes were the basis of Irish Magecraft, but what interested the boy was that the man was not drawing Irish runes, instead opting for Nordic ones. There was only one person someone could learn them from, his aunt Scathach! So this man studied under her to… that was perfect! If he was her student, then he would know who her greatest student was, and that could finally give the boy a goal! Hell, maybe this guy was her greatest student! 

With a smile stretched across his face, the boy reached down, picking up a rock that he placed in his sling, and spun the sling as he watched the man draw his runes. Algiz… Nauthiz... Ansuz... Inguz… the boy’s eyes widened as he realized that the man was invoking the spell Ath nGabla. Once it was in effect, the boy would be magically forced to accept the challenge, and neither of them could run from this fight. They’d fight until one couldn’t fight any more… or if one died. 

He had to end this quickly. 

As soon as the spell was set up, the man grinned at the boy. “Now, are you ready to---,” The boy wasted no time with a preemptive strike. Using his free hand, he traced a rune next to his sling, the spinning increasing rapidly after the rune was drawn. He then fired his rock right at the man’s head, a loud booming sound heard as the rock broke the sound barrier and sailed right for the older man. 

To the boy’s shock, despite the obvious surprise on his opponent’s face, the man moved his head out of the way almost immediately, the rock scraping by his cheek as it flew into the distance. 

“Sorry kiddo, but something like that won’t catch ol’ Cu Chulainn off guard!” the gentle look on the man’s face had morphed into one filled with battle lust. “Still, I can see how you gave Conall that huge bump on his head!” With that, Cu dashed forward towards the boy, the boy throwing his sling to the side and rushing at his opponent as well. 

The boy looked up to the man, their eyes locking to prevent the other from reading their next move. Cu threw a punch down at the smaller boy, who responded by hopping back, causing his opponent to miss him and over extend, which the young boy immediately took advantage of, slipping under the man’s arm and jumping up, wrapping his legs around the man’s shoulder while wrapping his arms around the man’s wrists and shifting his entire weight towards the ground. Cu fell to the ground as the boy proceeded to apply an arm bar to the man in hopes that he would give up. 

It wouldn’t be that easy. 

Instead of tapping out or even letting out a cry of pain, Cu instead opted to use his free hand to trace the air above him, the rune catching fire and launching at the boy, who was forced to let go of Cu’s arm and roll away to avoid being blasted face first with the fireball. The two were quickly back on their feet, Cu this time being even more aggressive, throwing quick but safe jabs at the boy he was facing. The boy managed to dodge every jab launched his way, but Cu’s aggressiveness made it hard for the boy to launch a counterattack. He couldn’t even make space between them, no matter how much he tried to back away, Cu would stick to him like he was the boy’s shadow, giving the boy barely any time to even plan.

However, barely any time was still time. Gritting his teeth, the boy lurched forwards, extending his finger and quickly tracing a trio of runes on Cu’s stomach. Disappointingly, he wasn’t fast enough to disengage and got a fist to the top of his head for his troubles. 

However, his plan worked, the first rune bursting into flames, while the second rune created a small pillar of ice that slammed into Cu’s stomach, causing the man to lose his balance as the final rune created a large gust of air, pushing the older man away and creating that much needed space between them. 

The two stared each other down, a grin now starting to form on the boy’s face. Something… something was different about this. All his life was nothing but training and fighting, but this fight was creating some sort of feeling inside of him. He just couldn’t place his finger on what it was. He didn’t have time to try to figure this out however as he needed to reposition himself, the boy running to the nearby group of rocks. Cu followed, his speed threatening to overtake the boy, but the boy had reached his goal. With a single leap, the boy kicked off a rock and spun in the air, throwing a kick that connected with Cu’s cheek, sending the older man back into the ground. 

Cu didn’t take it lying down, swinging his leg in a wide arc, kicking the boy’s feet out from under him the moment he landed before flipping onto his own feet, reaching over and burying his fist into the airborne kid’s stomach, sending him crashing into the ground. With a cough, the boy spun back up to his feet with the grace of a break dancer, gritting his teeth as he looked at Cu. The man’s much longer arms gave him a much better reach, and that made it hard for the young boy to actually land good hits on the Irish hero. Still, that’s what the rocks were for. He ran back to them, once again jumping off one, this time going for a flying kick directly at Cu, who raised his arm in order to block it. Before Cu could counterattack however, the boy kicked off the arm and flew back to the rocks, avoiding the hand that reached out to grab him. With a second kick off the rock, he managed to repeat his flying kick, this time knocking Cu flat on his back. 

This time, before Cu could get up, the boy grabbed his ankles and gritted his teeth, exerting effort as he began to spin around, dragging Cu across the sand. Faster and faster the boy spun, the centripetal force lifting Cu off the ground as they sped up. Finally, after reaching the fastest he could spin, the boy threw Cu up into the air, the man disappearing from the sight of all present. 

A second passed. The boy started to back up.

Five seconds passed, the boy now hopping in place as he waited.

Eight seconds passed, and the sound of Cu’s confused yelling filled the beach as he fell back to the earth.

Ten seconds passed, and the boy rushed ahead, leaping into the air and landing a dropkick on Cu’s chest before the man hit the ground, sending the older blue man crashing across the dirt, the attack causing the man to land far away enough that the boy could barely make out the details on the man.

And then suddenly the man was on top of him.

Glowing with a mystical power, he crossed the distance in less than a second and smashed his knee into the boy’s gut, the grin on his face wider than ever as the boy went flying… or he would have if Cu didn’t grab the young warrior’s ankle before he could get too far away, slamming the boy face first into the sand. 

“Come on, we’re going for a ride,” Cu said jokingly as he grabbed the back of the boy’s head and taking off with his new super speed, dragging the boy’s face across the sand as the man set a new running record across the beach. The trip down the beach abruptly came to an end as Cu decided to toss the boy in the air and punt him further down the beach, away from the rocks the boy was using. 

As he coughed up sand, the boy stood up, seeing Cu hadn’t moved yet. Quickly, he drew a rune on himself… and the world slowed down around him, everything now moving at a snail's pace… everything except for Cu, who was running at him. The boy dashed forward, his speed now matching Cu’s as the two powerful forces met, the fight breaking out into a flurry of punches and kicks. Despite their new speed, the two couldn’t break through the other’s defenses, each blocked attack echoing loudly around the beach. 

With neither fighter able to overpower the other, the boy made a new plan. Since Cu activated his speed increasing rune first, it wore off first, giving the boy a split second to slide under the older man’s legs and cross the distance back to the rocks. He jumped up, landing on the rock and about to attack, when he found himself staring into the whites of Cu’s eyes as the older warrior threw a punch. The boy couldn’t do anything but grab the fist to make sure he wouldn’t be hit. Gritting his teeth, the young warrior threw his own punch that was caught easily by Cu. Both out of options, they smashed their heads against the other’s, both trying to overpower the other. 

Despite the pain his body was in, despite the situation he found himself in, the boy couldn’t help but let out a joyous laugh.

“Oy, what’s so funny kid?” Cu asked playfully as he pushed harder. The boy pushed back with equal force before answering.

“I finally figured out what feeling this fight has been giving me. I’ve trained and fought all my life, either defeating my opponents in a few hits or being beaten senseless by my teachers, but now… now I met someone that’s a good fight… I’m finally having fun!” Cu’s grin only grew as he heard this, the kid’s grin perfectly mirroring it. After a few more futile seconds of trying to overpower each other, the two disengaged, staring at each other. The kid’s eyes darted to his spear, Cu’s gaze following it. 

The two ran off, Cu whistled while heading to his horse as the boy rushed to his spear. To the boy’s misfortune, the combination of Cu’s speed and the moving horse meant that the older warrior snagged his sword long before the kid could reach his spear, and chased him down, intent to intercept the child before he could reach his weapon. Gritting his teeth, the boy reached behind his cape, pulling out a short sword to block the swing. 

“Oh ho? I didn’t expect you to know how to use a sword,” Cu commented. 

“Come on, you should have figured out by now we had the same teacher,” the kid shot back. “There’s no way she’d let me leave if I couldn’t use all sorts of weapons,” The boy noticed the difference in their swords almost instantly. While the boy’s was just an ordinary short sword, Cu’s seemed to radiate some sort of holy light, filling the boy with both a feeling of warmth and dread simultaneously. 

“Admiring Cruaidín Catutchenn?” Cu teased. “I get the light’s pretty, but don’t get too distracted!” The two swords clashed, a dance of blades now filling the beach. However, the boy’s earlier problem was now exasperated. His short reach and smaller arm couldn’t counteract Cu’s longer limbs and weapon, making it even harder to even get close to him. 

At this rate, his defenses would be overwhelmed, and Cu could cut into him. There was only one way he could level the playing field.

Reaching behind his back, the boy pulled out another short sword, deflecting the sword of light away from him and hopping back away from Cu, taking a wide stance, leaving a large obvious hole in his defense. If he read Cu’s personality right, then this would work…

As the boy predicted, the older warrior went for the opening with a swift attack, one that was easily blocked. And then it happened again. And again. And again. Each false opening was quickly covered, allowing the boy to control the pace of the fight. 

Now that the attacks were under control thanks to the simple concepts of draws and feints on his side, the boy was able to look for an opening, and found one he did. 

The young boy leapt into the air, landing on the sword as it was stabbed at him, the boy then kicking off into the air, flipping over Cu’s head. With a quick swipe of his twin blades, the boy managed to shave off some of the top of Cu’s hair before landing gracefully on the ground. 

“Oh, so that’s the kind of game we’re playing?” Cu asked rhetorically as he turned around before raising the sword high over his head. The sword began to glow even brighter than it was before, the light for a brief second outshining even the sun. 

On instinct, the boy moved out of the way of the sword’s arc downwards, which turned out to be a great idea. As the sword swung down, it released a brilliant blue beam of energy that cut through the ground like a knife through warm butter. With a click of his tongue, the boy began to rapidly form a new plan. He quickly drew a rune on both of his short swords before launching them at Cu, the dual blades spinning through the air. 

Cu went to deflect the two weapons, but before he could, the swords began to glow, before exploding in a bright light, temporarily blinding the man. Groaning, the man brought both hands to his eyes, rubbing them in an attempt to bring relief to them. 

When his sight returned to him, Cu could see the boy had made it to his spear, the boy kicking the weapon into the air and snatching it up. With his new weapon in hand, the boy reared his arm back, focusing on Cu before launching his spear full force at the man. 

Cu readied his sword to defend, determined to swing and knock the spear out of its trajectory, but right before it got into his range, the boy suddenly appeared by the spear, the mystical power of the speed rune empowering the boy. Grabbing the weapon, the boy leapt into the air, twisting around until he was facing down at Cu and rapidly thrust his spear. Gritting his teeth, Cu was placed on the backfoot as he swung his sword rapidly in a desperate attempt to keep the attacks away, but the rain of attacks pierced through his defenses, covering his upper body and face with cuts. 

The boy soon landed though, and dashed towards Cu, rapidly attacking from a safe distance and preventing Cu from charging another sword beam. Even though Cu was able to keep the damage at a minimum, it took almost all he had to keep up with the boy’s flurry of attacks. 

“You’ve been holdin’ out on me, kid!” Cu stated with a frustrated grin. The boy’s only answer was to use his spear to pole vault up into the air and spin, swinging his lance at Cu’s face, who raised his sword to block the strike. “Alright, if I can’t get you with a sword, then I’ll just have to match your spear!” Upon hearing this, the boy used the blocked spear as leverage, spinning around and kicking Cu across the face, sending the warrior flying back towards the company of men watching them. 

Gritting his teeth, Cu hastily dropped his hand on the ground to stabilize himself as skidded to a stop. “Laeg!” He called out to the crowd. “Give me Gáe Bolg!” The boy dashed at Cu, determined to not let him get a new weapon, but as soon as he got close to Cu, the ground where the blue warrior’s hand had touched glowed with the power of a rune, exploding and blowing the boy away from the group.

A man from the crowd tossed Cu his requested weapon, a crimson spear that looked to be wrapped in thorns. Cu spun the spear in his hand, staring at it with a bit of trepidation in his eyes before shaking his head and grinning. “Only my brother has made me use this weapon before you,” He called out to the boy. “Today, you’ve become the warrior worthy of your parents’ expectations!” He gritted his teeth as he got into a stance. “But… today is also the day you die. I’m sorry it’s come to this, kid,” 

The boy stood back up, spinning his weapon and getting into a stance of his own, ready to throw the spear. “You’re not the first person that’s told me I’d die, and you won’t be the last! I won’t stop, not until I meet him!” The boy gritted his teeth as he realized he lost himself in the fun of the fight. He had to beat this man here, so he could move on. Either he killed Cu here, or he would need to take him down non-lethally. Did he take the easy way or the hard way…?

The two were so focused, they didn’t notice a woman riding up to the group, screaming for Cu to stop, yelling at all the men to stop the battle. The men watching turned to her, unwilling to touch the wife of Cu Chuliann, but also just as unwilling to let her interfere with the fight… until she screamed out one phrase that made them all turn pale, every man now turning and yelling at Cu to stop the fight.

It was too late though.

Their grips tighten around their weapons as the two warriors stared each other down, their spears lighting up with an aura matching their spear’s color. 

“Gáe…,”

“Gáe…,” Cu dashed forward, his spear glowing as he closed the distance between them, ready to thrust.

“Scrios!” At that moment, the choice was made. The boy’s green spear streaked through the air, the green aura surrounding it taking the form of the sea monster Coinchenn, the aura roaring as it flew at Cu. But then… the spear sailed by the man’s neck, the boy intentionally missing his target. He moved perpendicularly from Cu, confident that there was no way the thrust could hit him, which would allow him to jump behind Cu and choke him out.

 _ **“Bolg!”**_ What was a surefire plan for victory came crumbling down in an instant. No matter how much the boy moved, no matter how impossible the thrust angle Cu had to make, the crimson spear didn’t care. It pierced the boy’s heart with an unnatural precision, causing the boy to try to scream in pain, only to cough up blood instead. 

“She didn’t... teach me that…,” the boy managed to get out between coughs, staring in horrified wonder at the impossible thrust Cu had made. Cu sighed and patted the boy on the head gently. 

“You fought well… I’m sure your parents would be proud of you,” Cu offered, the sentiment doing little to ease the boy’s growing sense of dread. He really was dying… there was no way for him to meet his dad now, was there? The older man pulled out the cursed spear and turned to leave, obviously not wanting to see a young boy die to the curse of Gáe Bolg.

“W-wait…,” The boy croaked out before Cu could leave. “Could… could you do me a favor? Please?” Cu turned around to look at the boy with pity, before nodding. The boy dug into his pocket, pulling out the golden ring. “C-Can you find Scathach’s greatest student and g-give him this? T-tell him… I’m sorry I failed…,” As he held it out for Cu, the blue hair’s warrior’s face shifted immediately from a look of pity to a look of panic. 

“Connla?” Cu asked in a quiet voice, causing the now named boy to look up at Cu with surprise. 

“Y-you… you know my name?” Connla answered with his own question, only to get immediately wrapped in strong, warm arms. The little strength he had was rapidly draining from him now, although it was replaced with relief. He couldn’t lift his arms to hug his dad back, his body screamed out too much in pain to even attempt it, but that was okay. “D-Dad… I’m sorry I…,”

“Don’t be,” Cu’s voice interrupted. “I’m sorry, I’m so sorry kid. I didn’t…,” He broke the hug, looking Connla in the eye. “I want you to know, I am proud of you, son,” Connla looked into his father’s eyes, and he realized something.

They looked really warm… it was so different from the looks his mother or his aunt would give him, his memories filled with looks so cold and calculating. Was this what love was? Did… did his mother and aunt not love him at all? With this revelation setting in, tears began to flow down the boy’s face as Cu scooped him up in his arms, carrying him back towards the company of men waiting for them. 

Connla coughed once more, sending pain throughout his entire body. He hated that he was still crying in front of his dad, but he couldn’t stop it. Besides, there were more pressing things weighing on his mind, his lie of a life crumbling at the very end. Cu showed him to each man waiting there, each a warrior of something known as the Red Branch. Each one greeted him, and each one gave their blessing for Connla to join their ranks for the very last moments of his life.

The last person however, was the woman, who looked at the two with sadness. She gently ran her fingers through the boy’s hair, the foreign action somehow being comforting to the young boy. Cu could only laugh sadly as he watched Connla relax despite the pain.

“I think he would have benefited from you being in his life, Emer,” Cu mentioned as he watched the boy relax. Now that Connla had been introduced to everybody, Cu picked up Cruaidín Catutchenn, placing the holy sword to Connla’s throat. 

“Hey Dad…,” Connla spoke up as he looked up to Cu for the final time. “I’m glad… I’m glad I didn’t kill you… I’m glad I met you,” With those final words and a trembling hand, Cu slit the throat of Connla, saving him from suffering any more from Bolg’s curse.

And thus a green branch was pruned before it was able to grow.

**Author's Note:**

> Yeah, so that's the one-shot. I honestly love the idea of Connla as a servant, and I wanted to write about basically his only battle. It's real sad and boy do I have thoughts about it. 
> 
> Anyways, I hope you enjoyed. If enough people like this, I may do a few more oneshots about Connla being summoned in Chaldea. Because that's a powder keg just waiting to go off. Let me know what you all thought!


End file.
